SDR Cube

News via the NUE-PSK email list that over the weekend George N2APB presented and demonstrated a prototype of the SDR Cube project at the TAPR Digital Communications Conference in Vancouver, WA near Portland, Oregon.

The SRD Cube’s formal title is “A Portable Software Defined Radio Utilizing An Embedded DSP Engine for Quadrature Sampling Transceivers” and it was devised by George Heron, N2APB and Juha Niinikoski, OH2NLT.

N2APB's SDR Cube

N2APB's SDR Cube

A companion to his NUE-PSK modem, it’s designed to provide “a standalone SDR transceiver (no PC required) that is quite portable and trail friendly”.

“So far the most attention has come from the SDR Cube’s “live bandscope” showing a +/- 4 kHz spectrograph of band activity along the top of the graphic display.  Some preliminary pics are on the start of the website …“.

From his earlier 11 September email where the SDR Cube was first announced:

“a totally self-contained embedded SDR transceiver using a Softrock for the RF front end and a pc board implementation of an HF modem that couples tightly with the NUE-PSK Digital Modem.  The Cube is designed to fit into a 4” x 4” x 4” pre-cut black powder-coated aluminum enclosure containing all controls, blue graphic display showing the familiar band scope of spectrum signals, and the popular Softrock RXTX v6.3 board.”

The latest update this morning from George is that the pricing “is not yet established … but soon will be.  I think the cost of the parts and pcbs is around $100, so you can guess what the corresponding price might be.”

They’re aiming for the range of offerings (bare PCB, kit, assembled & tested etc) to be available in about six weeks. As well the plan is for there to be a direct digital connection between the SDR Cube and the NUE-PSK by the shipping date. In the meantime check out the pics at Also brief mention on WETNET.

UPDATE: George N2APB has posted some videos of the SDR Cube in action. There’s a 25′ overview and five shorter clips.

The website now (30 Sept 10) has much more information about the rig including hardware and software architecture diagrams, a photo gallery, a very detailed 26 page pdf of the TAPR DCC conference presentation (7.5MB) and this feature list.

  • Standalone SDR transceiver … no PC, portable, compact
  • Self-contained single band … based on the I/Q RF front end
  • Softrock-compatible … designed to interface with SR v6.3 RXTX, etc.
  • Low Power … 90ma (Cube), plus 100 ma (Softrock Rx) or 300 ma (Software Tx
  • Add-on RF Amp & Attenuator … good control of incoming RF, optimize some SR features.
  • Quadrature Sampling Clocking options … DDS, Si570, or I2C to target Softrock
  • Built-in Keyer … 1-50 wpm, Iambic A, B, or straight key
  • Popular HF modes … SSB, CW, AM, Digital (with special interface to NUE-PSK)
  • Special interface to NUE-PSK Modem … digital interface provides best quality
  • Graphic LCD Display … Provides clear indications of the many status and options
  • Bandscope … provides +/- 4 kHz spectrum visibility for Rx, signal monitor for Tx
  • Audio filtering … low corner 200Hz, high corners 700, 1500, 2400 or 3600Hz
  • Audio Output … Headphones or amplified speaker, Binaural Audio
  • Beeper … User interface clicks, code practice oscillator, and more
  • Frequency agility … Fast/Med/Slo tune, dual VFOs, memories, RIT/XIT
  • Menus … Calibration, all settings, system gain, sidetone frequency, etc
  • Software Upgradeable … Bootloader enables user to load new software versions
  • Open Source & Hardware

A new Yahoo Group has also been set up and info can be found at

LATER UPDATE: 14 Oct 2010 – Tobias DH1TW has posted a 75 minute interview with George N2APB on his website – complete with comprehensive ‘shownotes’.

Stephen Rapley, VK2RH, is a regular contributor to and writes from New South Wales, Australia. Contact him at [email protected].

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